An estimated 17.6 million American adults (8.5 percent) meet standard
diagnostic criteria for an alcohol use disorder* and approximately
4.2 million (2 percent) meet criteria for a drug use disorder. Overall,
about one-tenth (9.4 percent) of American adults, or 19.4 million
persons, meet clinical criteria for a substance use disorder 
either an alcohol or drug use disorder or both  according
to results from the 2001-2002 National Epidemiologic Survey on Alcohol
and Related Conditions (NESARC) reported in the current Archives
of General Psychiatry, Volume 61, August 2004.

Conducted by the National Institute on Alcohol Abuse and Alcoholism,
National Institutes of Health, the NESARC is a representative survey
of the U.S. civilian noninstitutionalized population aged 18 years
and older. With more than 43,000 adult Americans participating,
the NESARC is the largest study ever conducted of the co-occurrence
of psychiatric disorders among U.S. adults.

The NESARC is the first national epidemiologic survey to use the
Diagnostic and Statistical Manual of Mental Disorders-Fourth
Edition (DSM-IV) definitions of independent mood and
anxiety disorders to examine the comorbidity, or co-occurrence,
of mental health disorders. Independent mood and anxiety disorders
exclude transient cases of these disorders that result from alcohol
and/or drug withdrawal or intoxication, conditions that usually
improve rapidly without treatment once substance use ceases. The
distinction is important because the diagnosis of current mood and
anxiety disorders among active substance abusers is complicated
by the fact that many symptoms of intoxication and withdrawal from
alcohol and other substances resemble the symptoms of mood and anxiety
disorders and thus, the additional psychiatric disorder may be overlooked.

The NESARC results show substantial comorbidity between substance
use disorders and independent mood and anxiety disorders is pervasive
in the U.S. general population: About 20 percent of persons with
a current (at the time of the survey or within the past year) substance
use disorder experience a mood or anxiety disorder within the same
time period. Similarly, about 20 percent of persons with a current
mood or anxiety disorder experience a current substance use disorder.

NESARC results also indicate high rates of comorbidity among persons
who sought treatment for mood, anxiety, or substance use disorders.
The high rates of comorbidity among treated persons suggest that
primary care physicians, mental health specialists, and alcohol
and drug abuse specialists should assess patients for multiple mental
health disorders, the authors conclude.

It would be incorrect for health care professionals to assume
that the majority of mood and anxiety disorders are due to substance
intoxication or withdrawal and will remit when the patients stops
drinking, said Ting-Kai Li, M.D., Director, National Institute
on Alcohol Abuse and Alcoholism. These findings suggest that
treatment professionals should be prepared to treat or refer patients
in stable remission from substance use for comorbid mood and anxiety
disorders. Earlier research has demonstrated that, left untreated,
such disorders may lead to substance use relapse and other negative
outcomes.

This study does not resolve questions about causal mechanisms
that may underlie relationships between DSM-IV substance
use and mood and anxiety disorders, according to Bridget Grant,
Ph.D., Ph.D., Chief of the Laboratory of Epidemiology and Biometry,
Division of Intramural Clinical and Biological Research. Analyses
of data from NESARCs second wave in 2004-2005
will help to form a foundation for future etiologic research.

In a separate paper appearing in the current issue of the Journal
of Clinical Psychiatry [Volume 65:948-958], the authors of the
NESARC study reported findings on the prevalence of personality
disorders in the United States.

Full text of the Archives of General Psychiatry article
is available at http://archpsyc.ama-assn.org/.
For an interview with Dr. Grant, please call the NIAAA Press Office.

The National Institute on Alcohol Abuse and Alcoholism, a component
of the National Institutes of Health, U.S. Department of Health
and Human Services, conducts and supports approximately 90 percent
of the U.S. research on the causes, consequences, prevention, and
treatment of alcohol abuse, alcoholism, and alcohol problems and
disseminated research findings to science, practitioner, policy
making, and general audiences. Additional alcohol research information
is available at www.niaaa.nih.gov.

* Alcohol use disorders include (1) alcohol abuse, a condition
characterized by recurrent drinking resulting in failure to fulfill
major role obligations at work, school, or home; persistent or recurrent
alcohol-related interpersonal, social, or legal problems; and/or
recurrent drinking in hazardous situations, and (2) alcohol dependence
(also known as alcoholism), a condition characterized by impaired
control over drinking, compulsive drinking, preoccupation with drinking,
withdrawal symptoms, and/or tolerance to alcohol.